Irradiation-induced transient Creep of metals during pulsed irradiation

Comment on a paper concerning the enhancement of irradiation-induced creep of metals by pulsed irradiation

“…17-19 in Ref. 1 ) or light ion [6,91 beams, a transient enhancement was missing after beam shut-down but appeared at the beginning of successive beam-on periods in similar amounts. This phenomenon can be explained by thermal effects: mechanically soft materials such as pure and/or annealed metals may show significant plastic deformation due to excessive or inhomogeneous heating during switching-on the beam.…”

“…However, the early numerical evaluations [ 10, 113 overestimate the size of the enhancement due to two incorrect assumptions: 1) The vacancy mobility during the duty cycle is strongly underestimated by using vacancy migration enthalpies H, " far above the experimental values of 2) The temperature drop during the reactor off-phase is neglected. This overestimates the unbalanced vacancy fluxes at the beginning of the off-phase and underestimates the vacancy concentration present before the beginning of the next on-phase.…”